Measure performance of various ways to flatten (unroll) nested PowerShell objects

FlattenCustomObjects.ps1

<# Copyright 2022 zett42
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files 
(the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, 
publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. #>

$ErrorActionPreference = 'Stop'
Set-StrictMode -Version 3.0

#-------------------------------------------------------------------------------------------------------------------------------

Function Expand-PropertiesByQueue {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ValueFromPipeline)] [PSObject] $InputObject,
        [Parameter()] [string] $Separator = '/'
    )
    
    process {
        $queue = [Collections.Queue]::new()        
        $queue.Enqueue( [PSCustomObject]@{ Child = $InputObject; Path = $null } )

        while( $queue.Count ) {

            $item = $queue.Dequeue()

            foreach( $property in $item.Child.PSObject.Properties ) {
                
                $propertyPath = if( $item.Path ) { $item.Path + $Separator + $property.Name } else { $property.Name }

                if( $property.Value -is [PSObject] ) {
                    $queue.Enqueue( [PSCustomObject]@{ Child = $property.Value; Path = $propertyPath } )
                    continue
                }

                # Output property
                [PSCustomObject]@{ Path = $propertyPath; Value = $property.Value }
            }
        }
    }
}

#-------------------------------------------------------------------------------------------------------------------------------

Function Expand-PropertiesByQueueGeneric {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ValueFromPipeline)] [PSObject] $InputObject,
        [Parameter()] [string] $Separator = '/'
    )
   
    process {
        $queue = [Collections.Generic.Queue[Collections.Generic.KeyValuePair[string, PSObject]]]::new()        
        $queue.Enqueue( [Collections.Generic.KeyValuePair[string, PSObject]]::new( $null, $InputObject ) )

        while( $queue.Count ) {

            $item = $queue.Dequeue()

            foreach( $property in $item.Value.PSObject.Properties ) {
                
                $propertyPath = if( $item.Key ) { $item.Key + $Separator + $property.Name } else { $property.Name }

                if( $property.Value -is [PSObject] ) {
                    $queue.Enqueue( [Collections.Generic.KeyValuePair[string, PSObject]]::new( $propertyPath, $property.Value ) )
                    continue
                }

                # Output property
                [PSCustomObject]@{ Path = $propertyPath; Value = $property.Value }
            }
        }
    }
}

#-------------------------------------------------------------------------------------------------------------------------------

Function Expand-PropertiesByStack {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ValueFromPipeline)] [PSObject] $InputObject,
        [Parameter()] [string] $Separator = '/'
    )
    
    process {
        $stack = [Collections.Stack]::new()

        $stack.Push( [PSCustomObject]@{ 
            Path = $null
            Enumerator = $InputObject.PSObject.Properties.GetEnumerator()
        })

        :stackLoop while( $stack.Count ) {

            $item = $stack.Peek()

            while( $item.Enumerator.MoveNext() ) {
                    
                $property = $item.Enumerator.Current
                $propertyPath = if( $item.Path ) { $item.Path + $Separator + $property.Name } else { $property.Name }

                if( $property.Value -is [PSObject] ) {
                    # Pseudo-recurse into child objects
                    $stack.Push( [PSCustomObject]@{ 
                        Path = $propertyPath
                        Enumerator = $property.Value.PSObject.Properties.GetEnumerator()
                    })
                    continue stackLoop
                }

                # Output property
                [PSCustomObject]@{ Path = $propertyPath; Value = $property.Value }
            }

            $null = $stack.Pop()
        }
    }
}

#-------------------------------------------------------------------------------------------------------------------------------

Function Expand-PropertiesByStackGeneric {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ValueFromPipeline)] [PSObject] $InputObject,
        [Parameter()] [string] $Separator = '/'
    )
    
    process {
        $stack = [Collections.Generic.Stack[Collections.Generic.KeyValuePair[string, Collections.IEnumerator]]]::new()

        $stack.Push( [Collections.Generic.KeyValuePair[string, Collections.IEnumerator]]::new( 
            $null, 
            $InputObject.PSObject.Properties.GetEnumerator() 
        ))

        :stackLoop while( $stack.Count ) {

            $item = $stack.Peek()

            while( $item.Value.MoveNext() ) {
                
                $property = $item.Value.Current
                $propertyPath = if( $item.Key ) { $item.Key + $Separator + $property.Name } else { $property.Name }

                if( $property.Value -is [PSObject] ) {
                    # Pseudo-recurse into child objects
                    $stack.Push( [Collections.Generic.KeyValuePair[string, Collections.IEnumerator]]::new( 
                        $propertyPath, 
                        $property.Value.PSObject.Properties.GetEnumerator() 
                    ))
                    continue stackLoop
                }

                # Output property
                [PSCustomObject]@{ Path = $propertyPath; Value = $property.Value }
            }

            $null = $stack.Pop()
        }
    }
}

#-------------------------------------------------------------------------------------------------------------------------------

Function Expand-PropertiesRecursive {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ValueFromPipeline)] [PSObject] $InputObject,
        [Parameter()] [string] $Path,
        [Parameter()] [string] $Separator = '/'
    )
    
    process {
        foreach( $property in $InputObject.PSObject.Properties ){

            $propertyPath = if( $Path ) { $Path + $Separator + $property.Name } else { $property.Name }

            if( $property.Value -is [PSObject] ) {
                Expand-PropertiesRecursive $property.Value $propertyPath
                continue
            }

            [PSCustomObject]@{ Path = $propertyPath; Value = $property.Value }
        }
    }
}

#-------------------------------------------------------------------------------------------------------------------------------

class RecursivePropertyExpander {
    static [Object] Expand( [PSObject] $InputObject, [string] $Separator, [string] $Path ) {

        $result = foreach( $property in $InputObject.PSObject.Properties ) {

            $propertyPath = if( $Path ) { $Path + $Separator + $property.Name } else { $property.Name }

            if( $property.Value -is [PSObject] ) {
                [RecursivePropertyExpander]::Expand( $Property.Value, $Separator, $propertyPath )
                continue
            }

            # Output property
            [PSCustomObject]@{ Path = $propertyPath; Value = $property.Value }
        }        
        
        return $result
    }
}

Function Expand-PropertiesRecursiveClassMethod {
    [CmdletBinding()]
    param (
        [Parameter(Mandatory, ValueFromPipeline)] [PSObject] $InputObject,
        [Parameter()] [string] $Separator = '/'
    )
  
    process {
        [RecursivePropertyExpander]::Expand( $InputObject, $Separator, $null )
    }
}

#-------------------------------------------------------------------------------------------------------------------------------
# Sample data

$json = ConvertFrom-Json @'
{
    "New": {
        "App1": {
            "reply_urls": [
                "https://testapp1url1"
            ],
            "App1b": {
                "reply_urls": [
                    "https://testapp1url2"
                ],
                "App1c": {
                    "reply_urls": [
                        "https://testapp1url3"
                    ]
                }    
            }
        },
        "App2": {
            "reply_urls": [
                "https://testapp2url1",
                "https://testapp2url2"
            ],
            "App2b": {
                "reply_urls": [
                    "https://testapp2url3"
                ],
                "App2c": {
                    "reply_urls": [
                        "https://testapp2url4"
                    ]
                }
            }
        },
        "App3": {
            "reply_urls": [
                "https://testapp3url1",
                "https://testapp3url2",
                "https://testapp3url3"
            ],
            "App3b": {
                "reply_urls": [
                    "https://testapp3url4"
                ],
                "App3c": {
                    "reply_urls": [
                        "https://testapp3url5"
                    ]
                }
            }
        }
    },
    "Remove": {
        "object_id": [
            "foobar"
        ]
    }
}
'@

#-------------------------------------------------------------------------------------------------------------------------------
# Test output

Function Write-HeadLine( $s ) { "{0}`n{1}`n{0}" -f ('-' * 80), $s }

Write-HeadLine 'Expand-PropertiesByQueue'
$json | Expand-PropertiesByQueue | Out-Default

Write-HeadLine 'Expand-PropertiesByQueueGeneric'
$json | Expand-PropertiesByQueueGeneric | Out-Default

Write-HeadLine 'Expand-PropertiesByStack'
$json | Expand-PropertiesByStack | Out-Default

Write-HeadLine 'Expand-PropertiesByStackGeneric'
$json | Expand-PropertiesByStackGeneric | Out-Default

Write-HeadLine 'Expand-PropertiesRecursive'
$json | Expand-PropertiesRecursive | Out-Default

Write-HeadLine 'Expand-PropertiesRecursiveClassMethod'
$json | Expand-PropertiesRecursiveClassMethod | Out-Default

#-------------------------------------------------------------------------------------------------------------------------------
# Benchmark

'Running benchmark...'

# Time-Command.ps1 from https://gist.github.com/mklement0/9e1f13978620b09ab2d15da5535d1b27
. $PSScriptRoot\Time-Command.ps1

Time-Command -Count 50000 -ScriptBlock @(
    { $null = $json | Expand-PropertiesByQueue }
    { $null = $json | Expand-PropertiesByQueueGeneric }
    { $null = $json | Expand-PropertiesByStack } 
    { $null = $json | Expand-PropertiesByStackGeneric } 
    { $null = $json | Expand-PropertiesRecursive } 
    { $null = $json | Expand-PropertiesRecursiveClassMethod }
)

Performance measurement using Time-Command

Factor Secs (50000-run avg.) Command                                               TimeSpan
------ --------------------- -------                                               --------
1,00   0,000                 $null = $json | Expand-PropertiesByQueueGeneric       00:00:00.0002829
1,12   0,000                 $null = $json | Expand-PropertiesByQueue              00:00:00.0003177
1,28   0,000                 $null = $json | Expand-PropertiesByStackGeneric       00:00:00.0003611
1,37   0,000                 $null = $json | Expand-PropertiesRecursiveClassMethod 00:00:00.0003883
1,41   0,000                 $null = $json | Expand-PropertiesByStack              00:00:00.0003979
3,61   0,001                 $null = $json | Expand-PropertiesRecursive            00:00:00.0010212